Feature

Rheumatoid Arthritis: Abbott looking for a greater

Summary

In rheumatoid arthritis treatment a shift towards the earlier use of DMARDs has threatened the dominance of the NSAID class of drugs. This has opened up considerable opportunity for drugs such as Remi

In rheumatoid arthritis treatment a shift towards the earlier use of DMARDs has threatened the traditional dominance of the NSAID class of drugs. This has opened up considerable opportunity for drugs such as Remicade and Enbrel, the current DMARD leaders. With Abbott's Humira recently approved in the US and awaiting approval in Europe, Datamonitor looks at the other DMARDs capable of upsetting the applecart.

Arthritis is the collective term for a wide variety of diseases that affect the tissue and bone of joints. There are over 100 different types of arthritis with rheumatoid arthritis (RA) and osteoarthritis (OA) being the most prevalent and therefore offering the greatest potential for pipeline drug developments.

A growing market
Although there is no cure for RA, there is a wider range of drugs involved in the treatment of this disease. Similar pain killing drugs are used to treat RA as OA, however, RA disease progression can be slowed by the use of disease modifying anti- rheumatic drugs (DMARDs), which target the immune system to slow the immunological attack on the effected joint.

Whilst Pfizer has virtually guaranteed its continued dominance of the arthritis market through the acquisition of Pharmacia and the launch of second-generation COX-II products, there is a growing trend in the early aggressive use of DMARDs.

The DMARD class can be split into two groups, consisting of the older traditional DMARDs such as methotrexate and the newer biologics including the latest class of drugs known as TNF-antagonists which have emerged as a pivotal treatment for RA patients in whom traditional treatments have failed.

These drugs work by specifically blocking tumor necrosis factor alpha (TNF-a), a protein that plays a central role in the inflammatory responses of autoimmune diseases such as RA. Immunex's Enbrel and Centocor's Remicade currently lead the anti-TNF agents but there are now other candidates looking to assume control of this market.

R&D breakthrough
In December 2002, Abbott's Humira (also known as D2E7) became the first human monoclonal antibody approved for reducing the signs and symptoms and inhibiting the progression of structural damage in adults with moderately to severely active RA. As a fully human antibody, Humira does not need to be used in combination with immunosuppressants.

As highly targeted disease fighters, therapeutic monoclonal antibodies are revolutionizing the treatment of many illnesses including rheumatoid arthritis. These "magic bullets" work by engaging a patient's own immune system or suppressing the immune system to combat disease.

Datamonitor shares Abbott's high expectations for Humira, anticipating that the drug will be commercially successful due to its demonstrated efficacy, side effects and delivery regimen, compared to Enbrel and Remicade. Clearly buoyed by the Humira data in the ARMADA trials Abbott is now investigating potential wider indications for the drug.

After the earlier than expected approval of Humira in the US, Abbott is now awaiting the drug's approval in Europe. Humira faces arguably greater opportunity in Europe, together with the other DMARDs, where regulatory issues, cost constraints, and clinical uncertainty have all contributed the limited impact of COX-II inhibitor sales.

Competition is high
Datamonitor also recognizes the potential of Celltech's CDP 870 to make a significant impact in the RA market, with its launch expected in 2005. The product, also a TNF inhibitor, has been shown to be efficacious in reducing the signs and symptoms of RA and has a strong administration regimen - subcutaneous injection once every four weeks.

But the strongest feature of this product is its low cost production method compared to Enbrel and Remicade. This will allow the competitive pricing of CDP 870, which will promote the use of this product to biologic users and non-users. CDP 870's chances of success in the field of RA treatments will be boosted by the significant marketing backing of Pfizer.

Datamonitor believes that CDP 870 will pose a considerable threat to current and future biologics and could result in Enbrel and Remicade being used as second line products after CDP 870. In addition, products launched after CDP 870 such as AnervaX.RA r-TBI-1 and sTNFRI will be pushed towards the treatment of severe and refractory RA.

More to come
Over the next seven years, approximately 19 DMARDs are expected to be launched, and will be positioned in different areas of the RA market, dependent on efficacy, mechanism of action, side effects and cost. Unknown long-term side effects pose a large threat to the growth and expansion of the DMARD class, particularly amongst the biologics. However, this barrier to use will decrease as the understanding of, and experience with biologics increases.

DMARD market growth is currently being driven by new product launches, where previously old off-patent products dominated. Therefore, while growth is stimulated by increased uptake of these products, it is also driven by the increased cost of these therapies compared to the older drugs. Datamonitor forecasts that the DMARD drug class market will grow at a CAGR of 12.4% from 2001-2010, approaching $7.3 billion in sales in 2010.

Humira possesses a resistance profile likely to be comparable if not superior to Enbrel. In the case of Enbrel, a humanized monoclonal antibody, there is low potential for an in vivo antibody reaction against the product, and there is potentially far less of a reaction due to Humira's status as a fully human monoclonal antibody.

Another possible benefit of Humira is the compound's dosing regimen, scheduled as it is for once-fortnightly subcutaneous injection. This feature could allow it be the long-term therapy of choice in slowly progressing RA.

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